JPH0414770B2 - - Google Patents
Info
- Publication number
- JPH0414770B2 JPH0414770B2 JP59037988A JP3798884A JPH0414770B2 JP H0414770 B2 JPH0414770 B2 JP H0414770B2 JP 59037988 A JP59037988 A JP 59037988A JP 3798884 A JP3798884 A JP 3798884A JP H0414770 B2 JPH0414770 B2 JP H0414770B2
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- shutter
- light
- voltage
- optical
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000004973 liquid crystal related substance Substances 0.000 claims description 53
- 230000003287 optical effect Effects 0.000 claims description 31
- 238000000034 method Methods 0.000 claims description 30
- 230000010287 polarization Effects 0.000 claims description 9
- 210000004027 cell Anatomy 0.000 claims 1
- 210000002858 crystal cell Anatomy 0.000 claims 1
- 239000007788 liquid Substances 0.000 description 19
- 238000010586 diagram Methods 0.000 description 8
- 230000005684 electric field Effects 0.000 description 8
- 108091008695 photoreceptors Proteins 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 238000002834 transmittance Methods 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 4
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000004332 silver Substances 0.000 description 3
- 230000000903 blocking effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- -1 silver halide Chemical class 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 239000004988 Nematic liquid crystal Substances 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 238000011982 device technology Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
- G02F1/1333—Constructional arrangements; Manufacturing methods
- G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
- G02F1/133509—Filters, e.g. light shielding masks
- G02F1/133512—Light shielding layers, e.g. black matrix
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Liquid Crystal (AREA)
- Liquid Crystal Display Device Control (AREA)
- Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
- Exposure Or Original Feeding In Electrophotography (AREA)
Description
【発明の詳細な説明】
本発明は、液晶−光学シヤツタ等の光学変調素
子の駆動法に関し、詳しくは電子写真方式を利用
したプリンタの光シヤツタアレイに適用しうる新
規な液晶−光学シヤツタ等の光学変調素子の駆動
法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for driving an optical modulation element such as a liquid crystal-optical shutter, and more specifically to a method for driving an optical modulation element such as a liquid crystal-optical shutter, and more specifically, a method for driving an optical modulating element such as a liquid crystal-optical shutter that can be applied to an optical shutter array of a printer using an electrophotographic method. This invention relates to a method of driving a modulation element.
従来より、任意に光を透過あるいは遮断する光
学変調装置、すなわち光シヤツタは銀塩写真カメ
ラをはじめとして多くの用途に適用されている。
更に近年電子写真式プリンタの普及とともにその
小型化、高信頼性化のために上記光シヤツタをア
レイ状に構成して、電子写真感光体に光像を記録
することが考えられている。 2. Description of the Related Art Conventionally, optical modulators that transmit or block light as desired, that is, optical shutters, have been used in many applications including silver halide photographic cameras.
Furthermore, in recent years, with the spread of electrophotographic printers, in order to make them smaller and more reliable, it has been considered to configure the optical shutters in an array to record optical images on electrophotographic photoreceptors.
この様な光学変調装置に適用しうるものとし
て、電気光学変調素子としての液晶、PLZTな
ど、あるいは光磁気フアラデー効果を利用するも
のなどが提案されている。 As devices that can be applied to such optical modulation devices, liquid crystals, PLZT, and the like as electro-optic modulation elements, and devices that utilize the magneto-optical Faraday effect have been proposed.
このうち液晶を用いる方式のものはその製造の
容易性、低価格性、あるいは光学的変調を低電
圧、低電力で達成し得る点から早い時期から注目
されてきた。しかし液晶はその応答速度が遅い点
が欠点として挙げられ、例えば前記光シヤツタア
レイとして用いる場合においては高速度、高密度
で前記電子写真感光体に光像を書き込むには満足
しきれないものであるという先入観があつた。し
かしながら液晶を高速に動作させようとする努力
は長年重ねられ、近来になりようやくその応答速
度については改善がなされてきた。 Among these, methods using liquid crystals have attracted attention from an early stage because of their ease of manufacture, low cost, and the ability to achieve optical modulation with low voltage and low power. However, the disadvantage of liquid crystals is that their response speed is slow, and for example, when used as the optical shutter array, it is not satisfactory for writing optical images on the electrophotographic photoreceptor at high speed and high density. I had a preconceived notion. However, efforts have been made for many years to make liquid crystals operate at high speed, and only recently have improvements in their response speed been made.
従来この種の装置を実現するための高速応答の
液晶装置の技術としては、(1)二周波法によるも
の、(2)三極ゲート方式によるものがある。 Conventional high-speed response liquid crystal device technologies for realizing this type of device include (1) a two-frequency method and (2) a three-electrode gate method.
二周波法によるものは特開昭56−94377号公報
他に記述されているので、詳しい説明は省くが、
印加電圧の異る周波数に応じて、正の誘電異方性
と負の誘電異方性を示す液晶組成物を用い、選択
的に印加周波数を切換え、液晶を電界方向に配向
させる時と電界に対し垂直な方向に配向させる時
とで光学的に区別し得る原理に基いている。又、
三極ゲート方式は、第29回応用物理学関係連合講
演会講演予稿集P.126に記載されている様に液晶
に横電界を強制的に作用させることにより、液晶
の立下がり応答速度を速める工夫がなされてい
る。 The two-frequency method is described in Japanese Patent Application Laid-Open No. 56-94377 and other publications, so a detailed explanation will be omitted.
Using a liquid crystal composition that exhibits positive dielectric anisotropy and negative dielectric anisotropy according to the different frequencies of the applied voltage, the applied frequency is selectively switched, and when the liquid crystal is aligned in the direction of the electric field and when it is aligned with the electric field. It is based on the principle that optically differentiable can be achieved when the orientation is perpendicular to the opposite direction. or,
The three-pole gate method speeds up the falling response speed of the liquid crystal by forcing a transverse electric field to act on the liquid crystal, as described in the Proceedings of the 29th Applied Physics Conference, P.126. Efforts have been made.
前述の５周波法はオンとオフを数百Hz（低周
波）と数百ｋHz（高周波）の２周波を用いて切換
える駆動法であるが、これには、(1)複雑な波形を
形成する回路が必要である、(2)高周波を用いてい
るためにICと液晶を駆動させた時の消費電力が
大きい、(3)安定に動作することが難かしく、特
に、温度に対して不安定で温度補償回路が必要で
ある、という欠点がある。 The five-frequency method described above is a driving method that switches on and off using two frequencies of several hundred Hz (low frequency) and several hundred kHz (high frequency). (2) Since it uses high frequency, it consumes a lot of power when driving the IC and liquid crystal. (3) It is difficult to operate stably, especially unstable with respect to temperature. The disadvantage is that a temperature compensation circuit is required.
また、３極ゲート方式は、片側の電極をくし歯
状にして対向電極とくし歯電極間の電界制御とく
し歯電極間の電界制御により駆動するものである
が、これには、(1)電極パターンの設計が難かし
い、(2)ダイナミツク駆動に適していない、という
欠点がある。 In addition, in the three-electrode gate method, the electrode on one side has a comb-like shape and is driven by controlling the electric field between the opposing electrode and the comb-like electrode, and by controlling the electric field between the comb-like electrodes. (2) It is difficult to design, and (2) it is not suitable for dynamic drive.
本発明の目的は前述の欠点を解消した液晶−光
学シヤツタ等の光学変調素子の駆動法を提供する
ことにあり、特に電子写真方式を用いたプリンタ
に適した液晶−光学シヤツタの光学変調法を提供
することにある。 SUMMARY OF THE INVENTION An object of the present invention is to provide a method for driving an optical modulation element such as a liquid crystal-optical shutter that eliminates the above-mentioned drawbacks, and is particularly suitable for a printer using an electrophotographic method. It is about providing.
本発明の別の目的はシヤツタの誤動作を防止し
うる液晶−光学シヤツタ等の光学変調素子の駆動
法を提供することにある。 Another object of the present invention is to provide a method for driving an optical modulation element such as a liquid crystal-optical shutter that can prevent shutter malfunctions.
本発明による方法の第１の特徴は、偏光軸が
90゜又は略90゜の角度で交差する一対の偏光板間
に、前記偏光板の偏光軸に対して45゜あるいは略
45゜の角度の方向にホモジニアス配向した液晶を
挾持した一対の電極板からなる光学変調手段
（DAPモード光学変調手段）を有する液晶−光学
シヤツタを使用し、前記液晶に閾値電圧より大き
い電圧を印加させて遮光（オフ）状態を保持し、
液晶に印加されている電圧を消去することによつ
て透光（オン）状態を得ることにある。 The first feature of the method according to the invention is that the polarization axis
Between a pair of polarizing plates intersecting at an angle of 90° or approximately 90°, an angle of 45° or approximately 45° to the polarization axis of the polarizing plate.
A liquid crystal-optical shutter having an optical modulation means (DAP mode optical modulation means) consisting of a pair of electrode plates sandwiching a liquid crystal homogeneously aligned in the direction of an angle of 45 degrees is used, and a voltage higher than the threshold voltage is applied to the liquid crystal. to maintain the light-blocking (off) state.
The purpose is to obtain a translucent (on) state by erasing the voltage applied to the liquid crystal.
本発明で用いる液晶−光学シヤツタは、透光状
態を得るために、液晶がホモジニアス配向に復帰
できるのに十分に低い電圧印加状態、好ましくは
無電界状態とすることが必要であるが、この無電
界状態又は閾値電圧より小さい電圧状態によつて
生じた透光状態における光強度が振動する現象
（バウンジング現象）が現れることが、本発明の
研究により判明した。 In order to obtain a light-transmitting state in the liquid crystal-optical shutter used in the present invention, it is necessary to apply a sufficiently low voltage to allow the liquid crystal to return to a homogeneous alignment, preferably in a no-electric field state. The research of the present invention has revealed that a phenomenon (bouncing phenomenon) in which the light intensity oscillates in a translucent state caused by an electric field state or a voltage state lower than a threshold voltage occurs.
これを第１図に示す。 This is shown in FIG.
第１図は液晶に印加する電圧と透過率の変化を
時間軸に沿つて表わしたもので、通常V0の印加
電圧が付与されている時は、液晶分子の配列が電
界方向に向き、そのため遮光（オフ）状態が維持
されているが、印加電圧を閾値電圧以下（例えば
０ボルト）に切換えると、液晶分子の配列がホモ
ジニアス配向され透過（オン）状態が維持される
はずであるが、実際にはその透過状態の現出の仕
方は第１の透過率ピークP1、第２の透過率ピー
クP2をもつている。一般にこの現象をバウンシ
ング現象と呼んでいる。従つて、本発明方法の今
一つの特徴は、電圧印加による遮光状態から液晶
がホモジニアス配向に復帰できるのに十分に低い
電圧印加状態又は無電界状態へ変化後、光のバウ
ンシング現象の最初の透光状態のピークP1まで
の間に再び十分に高い電圧を印加する点にある。 Figure 1 shows the voltage applied to the liquid crystal and the change in transmittance along the time axis. Normally, when an applied voltage of V 0 is applied, the liquid crystal molecules are aligned in the direction of the electric field. The light-shielding (off) state is maintained, but if the applied voltage is switched to below the threshold voltage (for example, 0 volts), the arrangement of liquid crystal molecules should be homogeneous and the transmitting (on) state will be maintained, but in reality The transmission state has a first transmittance peak P 1 and a second transmittance peak P 2 . This phenomenon is generally called a bouncing phenomenon. Therefore, another feature of the method of the present invention is that after changing from the light shielding state due to the voltage application to the voltage application state low enough to allow the liquid crystal to return to the homogeneous alignment or the no electric field state, the first light transmission due to the light bouncing phenomenon is performed. The point is to apply a sufficiently high voltage again until the state reaches its peak P1 .
又、本発明で使用する液晶−光学シヤツタは、
液晶に閾値電圧より大きい電圧で、例えば20V以
上の電圧、好ましくは30V〜50Vの電圧を印加す
ることによつて遮光状態を形成することができ
る。この際、液晶に印加される電圧は交流を用い
ることが適しているが、直流であつても差しつか
えない。 Furthermore, the liquid crystal-optical shutter used in the present invention is
A light-blocking state can be formed by applying a voltage higher than the threshold voltage to the liquid crystal, for example, 20V or more, preferably 30V to 50V. At this time, it is suitable to use alternating current as the voltage applied to the liquid crystal, but direct current may also be used.
以上の説明から理解されるように、本発明によ
る液晶−光学シヤツタ等の光学変調素子の駆動法
は、偏光軸が90゜又は略90゜の角度で交差する一対
の偏光手段の間に、前記偏光手段の偏光軸に対し
て45゜又は略45゜の角度の方向にホモジニアス配向
した液晶を一対の電極板間に挾持した光学変調素
子の前記液晶に閾値電圧より大きい電圧を印加す
ることによつて遮光状態とし、そのうち選択され
た区域の液晶のみ閾値以下の低い電圧へ変化さ
せ、入射光の液晶分子による複屈折で光強度振動
が発生する最初の振幅のピークまでの間に再び閾
値電圧以上の大きい電圧を印加し前記選択された
区域を特定時間のみ透光状態とすることを特徴と
するものである。 As can be understood from the above description, the method for driving an optical modulation element such as a liquid crystal-optical shutter according to the present invention is such that the polarization axis of the optical modulator is intersected at an angle of 90° or approximately 90° between a pair of polarizing means. By applying a voltage higher than a threshold voltage to the liquid crystal of an optical modulation element, which has a liquid crystal homogeneously aligned in a direction at an angle of 45° or approximately 45° to the polarization axis of the polarizing means, and sandwiched between a pair of electrode plates. Then, the liquid crystal in the selected area is changed to a low voltage below the threshold value, and the voltage exceeds the threshold voltage again until the first amplitude peak at which light intensity oscillation occurs due to birefringence of the incident light due to liquid crystal molecules. The method is characterized in that the selected area is made transparent only for a specific time by applying a large voltage.
以下、本発明を図面に従つて説明する。 The present invention will be explained below with reference to the drawings.
第２図は本発明方法に使用される液晶−光学シ
ヤツタを示すもので、第２図ａは、液晶−光学シ
ヤツタの平面図を示し、第２図ｂは液晶の配向方
向と偏光軸の関係を示す説明図で、第２図ｃは第
２図ａのＡ−A′断面図である。 Figure 2 shows a liquid crystal-optical shutter used in the method of the present invention, Figure 2a shows a plan view of the liquid crystal-optical shutter, and Figure 2b shows the relationship between the orientation direction of liquid crystal and the polarization axis. FIG. 2c is a sectional view taken along line A-A' in FIG. 2a.
図中、１は共通電極、２は信号電極、３はシヤ
ツタ開口部、４，５は偏光板、７，８はガラスま
たはプラスチツクフイルム等の基板、９は液晶物
質を示す。液晶物質９は共通電極１と信号電極２
の間に挾持されていて、この液晶物質９は偏光板
４と５のそれぞれの偏光軸４′と５′に対して角度
45゜の方向６にホモジニアス配向されている。又、
この液晶−光学シヤツタはシヤツタ開口部３以外
の個所に遮光マスク１０が形成されている。 In the figure, 1 is a common electrode, 2 is a signal electrode, 3 is a shutter opening, 4 and 5 are polarizing plates, 7 and 8 are substrates such as glass or plastic film, and 9 is a liquid crystal material. Liquid crystal substance 9 has common electrode 1 and signal electrode 2
The liquid crystal material 9 is held at an angle to the polarization axes 4' and 5' of the polarizers 4 and 5, respectively.
It is homogeneously oriented in direction 6 at 45°. or,
In this liquid crystal optical shutter, a light shielding mask 10 is formed at a location other than the shutter opening 3.
本発明において用いられる液晶−光学シヤツタ
は、液晶物質９として正の誘電異方性をもつネマ
チツク液晶（Np液晶）を用いているので、共通
電極１と信号電極２には20V以上の電圧が印加さ
れて、常に遮光（オフ）状態が維持されている。
この様な液晶−光学シヤツタは、第３図に示す様
に光源と感光体の間に配置されて、光源からの光
線を遮断することができる。 Since the liquid crystal optical shutter used in the present invention uses nematic liquid crystal (Np liquid crystal) with positive dielectric anisotropy as the liquid crystal material 9, a voltage of 20 V or more is applied to the common electrode 1 and the signal electrode 2. The light-shielded (off) state is always maintained.
Such a liquid crystal-optical shutter can be placed between a light source and a photoreceptor, as shown in FIG. 3, to block light from the light source.
第３図は上記の液晶−光学シヤツタを電子写真
方式のプリンタに利用した態様を説明する図で、
上記の型式のシヤツタより成るシヤツタアレー２
０を光源２１と感光体ドラム２２の間に配置した
ものを示す。第３図において、光源２１は常に点
灯しており、液晶−光学シヤツタアレー２０を常
に照らしている。このシヤツタアレー２０は、液
晶駆動回路（図示せず）によつて光源２１よりの
光線が遮断されて、選択された区域を透光状態と
することによつて光信号を発生し、感光ドラム２
２に照射する光線を制御することができる。ま
た、光源２１からの光線とシヤツタアレー２０か
らの光信号の集光性を得るために、光路中にレン
ズ２３と２４を配置しておくことが望ましい。感
光ドラム２２は、光信号の照射に先立つて予めコ
ロナ放電装置などを備えた帯電ステーシヨン２５
でプラス又はマイナスに帯電され、感光ドラム２
２における光照射された所では、帯電電荷が消滅
して静電潜像が形成される。この様にして形成さ
れた静電潜像は、現像部２６で帯電時の極性と反
対極性又は反転現像による時には同一極性のトナ
ーとキヤリアからなる現像剤の存在下に現像バイ
アスを印加しながら磁気ブラシ現像法などによつ
て現像した後、転写部２７で像保持部材２８（例
えば、紙など）に転写し、次いで定着部２９で熱
や圧力などによつて定着され、完全に固定化され
たプリント物が得られる。 FIG. 3 is a diagram illustrating a mode in which the above-mentioned liquid crystal-optical shutter is used in an electrophotographic printer.
Shutter array 2 consisting of the above types of shutters
0 is placed between the light source 21 and the photosensitive drum 22. In FIG. 3, the light source 21 is always on and constantly illuminates the liquid crystal-optical shutter array 20. In FIG. The shutter array 20 generates an optical signal by blocking a light beam from a light source 21 and making a selected area transparent by a liquid crystal drive circuit (not shown).
It is possible to control the light rays irradiated to 2. Further, in order to obtain a condensing property for the light beam from the light source 21 and the optical signal from the shutter array 20, it is desirable to arrange lenses 23 and 24 in the optical path. Prior to irradiation with an optical signal, the photosensitive drum 22 is placed in a charging station 25 equipped with a corona discharge device, etc.
The photosensitive drum 2 is charged with a positive or negative charge.
In the area irradiated with light in step 2, the charged charges disappear and an electrostatic latent image is formed. The electrostatic latent image formed in this way is magnetically developed in the developing section 26 while applying a developing bias in the presence of a developer consisting of toner and carrier of the opposite polarity to the polarity at the time of charging, or of the same polarity when performing reversal development. After being developed by a brush development method or the like, the image is transferred to an image holding member 28 (for example, paper) in a transfer section 27, and then fixed in a fixing section 29 using heat, pressure, etc., and is completely fixed. Prints can be obtained.
シヤツタアレー２０から発生した光信号を受け
る感光体は、前述の如き電子写真方式のものに限
らず、例えば銀塩写真方式の感光体（例えば、モ
ノクロペーパー、カラーペーパー、米国スリーエ
ム社「ドライシルバー」など）であつてもよい。 The photoreceptor that receives the optical signal generated from the shutter array 20 is not limited to the electrophotographic type described above, but also a silver halide photoreceptor (for example, monochrome paper, color paper, Dry Silver from 3M Co., Ltd. in the United States, etc.). ).
本発明は上記の液晶−光学シヤツタを使用し、
前記液晶に閾値電圧より大きい電圧を印加するこ
とによつて遮光状態とし、そのうち選択された区
域の液晶のみ閾値以下の低い電圧へ変化させ、入
射光の液晶分子による複屈折で光強度振動が発生
する最初の振幅のピークまでに再び閾値電圧以上
の大きい電圧を印加し前記選択された区域を特定
時間のみ透光状態とする。 The present invention uses the above liquid crystal-optical shutter,
By applying a voltage higher than the threshold voltage to the liquid crystal, a light-shielding state is created, and only the liquid crystal in a selected area is changed to a lower voltage below the threshold, causing light intensity oscillation due to the birefringence of the incident light due to the liquid crystal molecules. Until the peak of the first amplitude, a voltage higher than the threshold voltage is again applied to make the selected area transparent for a specific period of time.
以下、第４図を参照して説明する。 This will be explained below with reference to FIG.
前述の液晶−光学シヤツタの共通電極１には、
第４図に示す波形Ａが印加され、期間T1，T3，
…では全ての信号電極２には第４図に示す波形Ｂ
が印加されることにより液晶物質９には波形Ａ−
Ｂが付与される。これにより期間T1，T3，…で
は液晶物質９の分子は共通電極１と信号電極２の
方向に垂直配向して、光源からの光線は偏光板４
と５で遮断される。 The common electrode 1 of the above-mentioned liquid crystal-optical shutter includes:
Waveform A shown in FIG. 4 is applied, and periods T 1 , T 3 ,
...Then, all signal electrodes 2 have the waveform B shown in FIG.
As a result, the liquid crystal material 9 has a waveform A-
B is given. As a result, during periods T 1 , T 3 , ..., the molecules of the liquid crystal material 9 are aligned perpendicularly to the direction of the common electrode 1 and the signal electrode 2, and the light rays from the light source are directed to the polarizing plate 4.
and 5.
この液晶−光学シヤツタは、期間T2，T4，…
で選択された信号電極２には波形Ｂが付与され、
この区域の液晶には電圧無印加状態となつて、配
向方向６のホモジニアス配向に復帰することがで
きる。この際、直線偏光光に対して液晶分子が
45゜の角度を有しているため、直線偏光光が前述
の配向方向を有する液晶層で脱偏光
（depolarization）され、偏光板５を透過し、シ
ヤツタが開口される。この際、期間T2，T4，…
は100msec以下、好ましくは50msec以下の時間
とすることが必要でT2，T4，…を100msec以上
の時間で維持すると前述した様にバウンシング現
象が現われる。第４図Ｃは、期間T1，T2，T3，
T4，…における光学変化（T1遮光−T2透光−T3
遮光−T4透光…）を示しており、期間T2，T4で
例えば光源からの光線が選択されたシヤツタ開口
部３を通して感光体に到達することができる。 This liquid crystal-optical shutter has periods T 2 , T 4 ,...
Waveform B is given to the signal electrode 2 selected in
No voltage is applied to the liquid crystal in this area, and the homogeneous alignment in the alignment direction 6 can be restored. At this time, liquid crystal molecules react to linearly polarized light.
Since the angle is 45 degrees, the linearly polarized light is depolarized in the liquid crystal layer having the above-mentioned alignment direction, passes through the polarizing plate 5, and the shutter is opened. At this time, periods T 2 , T 4 ,...
It is necessary that T 2 , T 4 , . . . be maintained at a time of 100 msec or less, preferably 50 msec or less, and as described above, a bouncing phenomenon occurs. FIG. 4C shows periods T 1 , T 2 , T 3 ,
Optical change at T 4 ,... (T 1 light shielding − T 2 light transmission − T 3
(light blocking - T4 light transmission...), and during periods T2 and T4 , for example, light rays from a light source can reach the photoreceptor through the selected shutter opening 3.
本発明によれば、周波数10kPH、実効電圧30V
の交流電圧を1msecの時間で共通電極と全ての信
号電極に印加したところ、透過率は1.5％であつ
たが、選択された信号電極に共通電極に印加した
波形と同相の波形を付与して、かかる区域の液晶
に印加される電圧を０としたところ、透過率が20
％にまでなることが判明した。 According to the invention, frequency 10kPH, effective voltage 30V
When an AC voltage of 1 msec was applied to the common electrode and all signal electrodes, the transmittance was 1.5%. , when the voltage applied to the liquid crystal in this area is set to 0, the transmittance is 20
It was found that up to %.
又、第４図Ａ−Ｂに示した様に期間T1とT3で
液晶に印加される電圧が、それぞれ逆相の関係を
有することによつて、液晶に付与される直流成分
を０とすることが好ましい。 In addition, as shown in FIG. 4A-B, the voltages applied to the liquid crystal during periods T1 and T3 have an opposite phase relationship, so that the DC component applied to the liquid crystal can be reduced to 0. It is preferable to do so.
第１図に示すバウンシング現象が現れるDAP
モード光学変調手段を用いた本発明の駆動法によ
れば、電子写真方式に適用した際には、従来の二
周波法や三極ゲート法を用いた電子写真方式と比
較して、(1)高速のプロセス・スピードが達成さ
れ、(2)高いコントラストが得られ、(3)回路設計が
容易となり、(4)温度依存性を考慮する必要がなく
なる、という効果をもつ。 DAP where the bouncing phenomenon shown in Figure 1 appears
According to the driving method of the present invention using a mode optical modulation means, when applied to an electrophotographic method, compared to an electrophotographic method using a conventional two-frequency method or a triode gate method, (1) It has the following effects: high process speed is achieved, (2) high contrast is obtained, (3) circuit design is facilitated, and (4) there is no need to consider temperature dependence.
第１図はバウンシング現象を説明する説明図で
ある。第２図ａは、本発明に用いられる液晶−光
学シヤツタの平面図、第２図ｂは偏光板の偏光軸
と液晶の配向方向の関係を示す説明図、第２図ｃ
は第２図ａのＡ−A′断面図である。第３図は、
本発明を電子写真方式プリンタに適用した態様を
示す説明図である。第４図Ａは共通電極に印加す
る波形の説明図、第４図Ｂは信号電極に印加する
波形の説明図、第４図Ａ−Ｂは液晶に印加される
波形の説明図、第４図ｃは液晶−光学シヤツタの
時間における光学変化の態様を示す説明図であ
る。
１……共通電極、２……信号電極、３……シヤ
ツタ開口部、４，５……偏光板、４′，５′……偏
光軸、６……液晶配向方向、７，８……基板、９
……液晶、１０……遮光マスク。
FIG. 1 is an explanatory diagram illustrating the bouncing phenomenon. Figure 2a is a plan view of the liquid crystal-optical shutter used in the present invention, Figure 2b is an explanatory diagram showing the relationship between the polarization axis of the polarizing plate and the alignment direction of the liquid crystal, and Figure 2c
is a sectional view taken along line A-A' in FIG. 2a. Figure 3 shows
FIG. 1 is an explanatory diagram showing an aspect in which the present invention is applied to an electrophotographic printer. Fig. 4A is an explanatory diagram of the waveform applied to the common electrode, Fig. 4B is an explanatory diagram of the waveform applied to the signal electrode, Fig. 4A-B is an explanatory diagram of the waveform applied to the liquid crystal, Fig. 4 FIG. 3c is an explanatory diagram showing the mode of optical change over time in a liquid crystal-optical shutter. 1... Common electrode, 2... Signal electrode, 3... Shutter opening, 4, 5... Polarizing plate, 4', 5'... Polarizing axis, 6... Liquid crystal alignment direction, 7, 8... Substrate , 9
...LCD, 10...Light-blocking mask.
Claims (1)
数のシヤツタ開口部を形成し、該共通電極と複数
の信号電極との間に配置したホモジニアス配向の
液晶を有する液晶セル及び偏光軸が90゜又は略90゜
の角度で交差し、前記液晶セルを挟持した一対の
偏光手段であつて、該偏光軸が前記ホモジニアス
配向の方向に対して45゜又は略45゜の角度の方向と
なる一対の偏光手段を備えた光シヤツタアレイの
駆動法において、 前記複数のシヤツタ開口部に、前記液晶の閾値
電圧より大きい電圧を印加することによつて、該
複数のシヤツタ開口部を遮光状態とし、 そのうち選択されたシヤツタ開口部にのみ、前
記液晶の閾値電圧より小さい電圧を印加すること
によつて、該選択されたシヤツタ開口部を透光状
態とし、 前記透光状態の光強度振動における最初の振幅
のピークに達する前に、前記選択されたシヤツタ
開口部に、前記液晶の閾値電圧より大きい電圧を
印加することによつて、該選択されたシヤツタを
遮光状態とする、 ことを特徴とする光シヤツタアレイの駆動法。[Scope of Claims] 1. A liquid crystal having a plurality of shutter openings formed at the intersections of a common electrode and a plurality of signal electrodes, and having a homogeneously aligned liquid crystal disposed between the common electrode and the plurality of signal electrodes. A pair of polarizing means sandwiching the liquid crystal cell, wherein the cell and the polarization axis intersect at an angle of 90° or approximately 90°, and the polarization axis is at an angle of 45° or approximately 45° with respect to the direction of the homogeneous alignment. In a method of driving an optical shutter array including a pair of polarizing means in angular directions, the plurality of shutter openings are controlled by applying a voltage higher than a threshold voltage of the liquid crystal to the plurality of shutter openings. by applying a voltage smaller than the threshold voltage of the liquid crystal only to the selected shutter opening, the selected shutter opening is brought into a light-transmitting state; and the light intensity in the light-transmitting state is reduced. Before reaching a first amplitude peak in the vibration, applying a voltage greater than a threshold voltage of the liquid crystal to the selected shutter opening, thereby placing the selected shutter in a light-shielding state. Characteristic driving method of optical shutter array.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59037988A JPS60182421A (en) | 1984-02-29 | 1984-02-29 | Driving method of optical modulating element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59037988A JPS60182421A (en) | 1984-02-29 | 1984-02-29 | Driving method of optical modulating element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60182421A JPS60182421A (en) | 1985-09-18 |
| JPH0414770B2 true JPH0414770B2 (en) | 1992-03-13 |
Family
ID=12512945
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59037988A Granted JPS60182421A (en) | 1984-02-29 | 1984-02-29 | Driving method of optical modulating element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60182421A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62150330A (en) * | 1985-12-25 | 1987-07-04 | Sharp Corp | Liquid crystal shutter driving method and liquid crystal optical printer gradation recording method utilizing said method |
| JPH061312B2 (en) * | 1986-02-20 | 1994-01-05 | 富士写真フイルム株式会社 | LCD drive controller |
| US4836654A (en) * | 1986-06-30 | 1989-06-06 | Casio Computer Co., Ltd. | Drive method for a dual-frequency, dielectric anisotropy liquid crystal optical device |
-
1984
- 1984-02-29 JP JP59037988A patent/JPS60182421A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60182421A (en) | 1985-09-18 |
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